Method for manufacturing actuator device and liquid ejecting head including actuator device prepared by the method

A method is provided for manufacturing an actuator device including a substrate, a vibration plate, lower electrode, and a piezoelectric element having a piezoelectric layer, and an upper electrode. The vibration plate is formed by forming an insulating film comprised of a columnar crystalline zirconium layer whose surface has an average crystal grain size of about 20 to 50 nm on one surface the substrate, and then thermally oxidizing the zirconium layer into a columnar crystalline zirconium oxide layer whose surface has an average crystal grain size of about 20 to 50 nm. The zirconium layer shows an XRD pattern having a (002) plane peak with an FWHM of 0.4 or less. The piezoelectric element is formed on the lower electrode.